1. Field of the Technology
This disclosure pertains generally to digital camera focus control, and more particularly to estimating the direction of defocus within a digital camera.
2. Background Discussion
In digital photography it is often important to know the distance, in units of depth of field (DOF), between the present position and the in-focus position of the focus plane. It will be noted that when capturing an image using a digital camera, the captured image will be defocused if the target object is not on the focus plane. Although it is possible to know the distance in units of depth of field (DOF) from the object to the focus plane by estimating the defocus blur, it is unknown using current methods whether the object is in front or behind the focus plane. It should be appreciated, that the same distance in DOF in front or behind the focus plane will result in very similar amount of defocus blur. Present techniques do not overcome this significant ambiguity during depth estimation and auto focusing.
Accordingly, the present disclosure describes a mechanism for readily determining the direction of defocus, which overcomes the shortcomings of previous defocus estimation techniques.